Various methods of sterilization and disinfection have been used for the sterilization of different types of disposable and reusable medical equipment. Among these methods, a method of sterilization and disinfection by steam or by dry heat has been used extensively used. However, this method of sterilization and disinfection cannot be applied to sterilize materials that are adversely affected by such heat or steam.
Ethylene oxide (EtO) gas has also been used but suffers from the drawback that it may leave toxic residues on the articles to be sterilized, which may have adverse effects on patients who come into contact with such articles. Consequently, with this method, an additional procedure required to remove residual ethylene oxide from some sterilized items also causes the ethylene oxide sterilization procedure to be high in cost and to take a long in time.
Among methods for overcoming the aforesaid drawbacks, there is a method using hydrogen peroxide as a precursor of active species in a low temperature plasma system. This method is generally carried out in such a way that an object to be sterilized and disinfected is first brought in to contact with gaseous hydrogen peroxide as a pre-treatment, and the object is finally sterilized and disinfected by hydrogen peroxide plasma generated by supply of a required amount of electric power, so as to reduce a length of time required to sterilize and disinfect by plasma.
In the above low temperature plasma disinfection system, an apparatus for supplying hydrogen peroxide employs a capsule type cassette system containing a certain amount of hydrogen peroxide solution. The hydrogen peroxide solution contained in the capsule is fed to a solution-feeding pipe by means of an injection pump, and the fed hydrogen peroxide solution in a liquid phase is vaporized by a vaporizer, which is then fed into a sterilization reactor.
With the above capsule type cassette system, however, a used cassette must be replaced by a new one with ten capsules in it after the sterilization process is carried out ten times since one capsule is used in one sterilization process. In addition, the above vaporizer has drawbacks that the above apparatus for supplying an extremely small fixed amount of liquid is very complicated and very expensive.